1. Field of the Invention
The present invention relates to a digital electrophotographic copying apparatus and, particularly, relates to an image-storing, digital electrophotographic copying apparatus in which image data obtained by reading a document are stored before being printed.
2. Discussion of the Related Art
An image-storing, digital electrophotographic copying apparatus comprising a document reading means, an image storage means for temporarily storing image data obtained from the document reading means, and an image printing means for printing copies according to an electrophotographic process based on the image data stored in the image storage means is known in the art. This type of copying apparatus typically performs many functions which may include electronic recirculating document handling (RDH), reverse output processing, sample copying, etc.
A conventional image-storing digital electrophotographic copying apparatus generally starts a printing job only after the image printing means is ready for operation because copy printing is the final object of the electrophotographic copying apparatus. It is, therefore, typically impossible to operate the electrophotographic copying apparatus before completion of a image printing means start-up process. Furthermore, the time required for this start-up process, that is the time required for the image printing means to become ready for operation following application of electrical power to the electrophotographic copying apparatus, is usually longer than the time required for the document reading means and the image storage means to become ready for operation. As a result, the conventional electrophotographic copying apparatus requires an operator to wait for between 5 to 10 minutes before the entire electrophotographic copying apparatus becomes ready for operation.
Similarly, when the temperature of the fuser in the image printing means becomes lower than a fusing failure temperature it is necessary to interrupt the printing operation and reheat the fuser. When this so-called fusing failure occurs the conventional electrophotographic copying apparatus cannot be used until the fuser has reheated, and during the 3 to 7 minutes required for the fuser to reheat the operator cannot conduct substantive copying work.
It is also typically the case that the interruption of the printing job following a fusing failure is determined only on the basis of a comparison between the fuser temperature and the fusing failure temperature. Accordingly, when the temperature of the fuser reaches the fusing failure temperature just before the completion of a printing job, the job is kept waiting and the time required for completion of the job may be significantly and unnecessarily increased.